The Molecular Biology Module provides services involved with the production of transgenic, knock-out and knock-in mice and construction of gene constructs used for an array of applications (e.g., in situ hybridization probes), preparation of DNA clones and probes, and consultation or direct service for the design of polymerase chain reaction primers and optimization of reaction conditions. The module also provides limited- scale DNA sequencing, consultation or direct services for phosphorimaging and flow cytometry for cell analysis, and maintenance and oversight of shared molecular biology instrumentation. The module occupies a new laboratory designed for its exclusive use. The module is staffed by two full-time molecular biology technicians with advanced skills in molecular cloning, DNA manipulations, animal husbandry and microinjection. The services of this module enhance the environment for research by making molecular biology an accessible tool for any member of the vision core group. The environment is further enhanced by providing training and support in the use of modern shared instrumentation for molecular biology, including the STORM phosphorimager and Beckman Coulter FC500 flow cytometer.